1. Field of the Invention
The present invention relates to an image-processing apparatus and a method, and particularly relates to an apparatus and a method that are provided to transcode compressed and encoded video data.
2. Description of the Related Art
Encoding systems such as the Moving Picture Experts Group Phase-2 (MPEG-2) encoding system have been established as technologies for compressing and encoding image data. Manufacturers have developed and commercialized image-pickup devices including digital cameras, digital video cameras, and digital-versatile-disk (DVD) recorders that are configured to record image data (especially video data) under the MPEG-2 encoding system. Users can play recorded image data back by using the above-described devices, or a personal computer, a DVD player, and so forth.
A bit rate can be changed by temporarily decoding video data compressed and encoded under the MPEG-2 encoding system and re-encoding the decoded video data. The above-described technology is usually referred to as transcoding. The transcoding technology is usually performed to reduce a data amount. Namely, video data is re-compressed at a bit rate lower than that used before the transcoding is performed. For example, encoded video data recorded through the digital video camera, the encoded video data corresponding to a plurality of DVDs, can be recorded onto a single DVD through transcoding.
A variable-bit-rate (VBR) encoding system has been established for increasing the encoding efficiency of the MPEG-2 encoding system. The VBR encoding denotes a method of variably controlling a bit rate according to the complexity of image data and/or the magnitude of movement in each of frames of video data.
Technologies of encoding the video data corresponding to a scene in which a user is interested with high image quality by changing a bit rate based on a viewing history describing the contents, performers, or other characteristics of a program viewed by the user are available. One of the above-described technologies is disclosed in Japanese Patent Laid-Open No. 2004-186845.
The technology disclosed in Japanese Patent Laid-Open No. 2004-186845 allows for encoding video data corresponding to a scene showing a performer who had been viewed by the user with high image quality, for example.
However, not all the scenes showing the performer who had been viewed by the user is of interest to the user. On the contrary, such scenes may be of little interest to the user and the user may not wish to view the scenes. Therefore, encoding all video data corresponding to a scene(s) determined based on an appearance of the performer in such scene(s) with high image quality may lead to a waste of a recording medium.